My immobilizer fix (3 Viewers)

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Well, what a find this thread was!

Little bit of a story.

I've had my Hundy for a few years now and it's gone from full grandpa spec to a bit of an offroad tourer.

Anyways, back in Dec 2024 I was heading away for a long weekend to do some motorbike riding with some friends, taking the bike on the trailer behind the hundy and camping.

Had a great weekend. But on the way home we lost power steering and all the dash lights came on. Quickly pulled over and found the fan had deleted itself from the fan-bracket. I've since learnt, if you have a hundy long enough, you'll know the fan brackets fail.

Anyways, got towed to my sisters place as it was closer than our place (by about 270km) and let it sit while I waiting on replacement fan bracket.
Got it right before Christmas and over the holidays headed over to my sisters to install the new bracket.
Started disassembling and found we had no coolant....didn't see it until now but found 3 of the radiator fins had been cut right at the bottom. So now I also needed a new radiator.
Place another order and wait.

That arrived and I travelled back to my sisters to install it all.
Finished everything and topped coolant ready to bleed it all etc.
Truck wouldn't start. Crank, no start.

Now, I know after finding this thread, easy to test....and fix.

But at the time, all I could think of was that I'd stuffed something up on the repair of the fan bracket.
Was it the cam sensor? As you need to unplug it and thread the wire through the cover.
Was it the crank sensor? Had some debris dropped down into the cavity when the fan bracket disintegrated.
Was it something else?

To shorten the story now, I had to do 2 more trips across the country to try various things....and ordered replacement cam, crank, MAF sensors - just in case as I didn't want to have to wait and travel more times without having parts on hand.
In the end I couldn't work out why it wouldn't start....so begrudgingly asked the local mechanic if he could check it out at some point.

Back at home my mates were giving me crap for not having a rig to go wheeling....
So I thought I'd give it one more shot and check out the fuse locations and trace my kill switch to ensure nothing had happened with any of the wiring - as it really did seem like an electrical fault.

First google search, found this thread. Read it start it finish and was thinking this sounds EXACTLY like what I'm experiencing.

Told the mechanic to hold fire....made up the test lead and as I was over that side of the country for a MTB ride I decided to pop to my sisters and test it.

I was VERY happy to have the thing fire up after 3 months and lots of wasted trips (and money on spare parts I didn't need).
Anyways, thanks to this community for solving this very inconvenient coincident.
I've now made up the full harness and will be heading back across the country in April to finish the reassembly and hopefully drive the rig home.
Finally started!

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Thanks @medtro, another 100 series made it home. I’ve been wiggling the fuse and relay for the last week, last night that routine failed to get it started and I drove home from work with a jumper wire straight from the battery. Made it home without exploding anything, and bypassed it with your method. New fuse box is on the way from Dubai but I think I’ll leave it on the shelf until either this fails, something else in there fails or I sell the rig.
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About a month ago my 2006 had a no start issue. After about 5 minutes, it started right up. A week later, random no start. I went inside, started researching, 15 minutes I went back out and it started right up. Since then I've found the post "Troubleshooting instructions for newer UZJ100/LX470, post #117.", made a jumper wire to do the test once it happens again, and removed/reinstalled the relay just to make sure I could get it out. Then I waited for it to happen again... and waited... and waited...

FINALLY!!! Today no start in my driveway! I've never been so happy about a no start. I popped the hood, tapped the relay mentioned in post #117, and the truck started right up.

So I'm guessing its just a relay going bad? Does that make sense?
Just a follow up. Today at a gas station I had a crank, no start issue. It acted exactly the same as before. I tapped on the relay with my hand and the truck started right up.
That efi relay was very expensive! @medtro I'm going to message you about cost. Thanks
 
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Just a follow up. Today at a gas station I had a crank, no start issue. It acted exactly the same as before. I tapped on the relay with my hand and the truck started right up.
That efi fuse was very expensive! @medtro I'm going to message you about cost. Thanks
Did you have flashing security light when it didn't want to start? Could it be your relay is bad?
 
Thanks @medtro, another 100 series made it home. I’ve been wiggling the fuse and relay for the last week, last night that routine failed to get it started and I drove home from work with a jumper wire straight from the battery. Made it home without exploding anything, and bypassed it with your method. New fuse box is on the way from Dubai but I think I’ll leave it on the shelf until either this fails, something else in there fails or I sell the rig.
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Do you have a link for the new fuse box you ordered?
 
Did you have flashing security light when it didn't want to start? Could it be your relay is bad?
I was too frazzled to check in the moment. If it happens again hopefully I'll be able to slow myself down and check. The relay is about 1 year old OEM so if the new one is starting to act up... I don't know.
 

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